How to Know If Your Old Canned Food is Safe to Eat

We’ve all had that moment when we’ve opened up a can of food only to realize exactly how old it is and wonder whether or not it’s safe for consumption. This isn’t a question you should take lightly. If the food is bad and you eat it, the result could be a very painful death.

The biggest danger presented by old, spoiled canned foods is Clostridium Botulinum, a bacteria that triggers an illness we know as botulism. It’s one of the deadliest bacteria’s, so potent that a single teaspoonful of Clostridium Botulinum has the power to result in 100,000 deaths. One of the worse things about Clostridium Botulinum is that unlike other bacteria’s, heating the food doesn’t kill the spores. The only way to kill any spores is with a pressure canner.

Check the Seals

If the high pressure canning process has gone smoothly, you should hear a distinctive popping noise as the two piece lids cool. The sound is created by the lids being drawn into the jar’s vacuum. If there’s no pop, the canning process didn’t take.

Even though you probably tested the cans when you put them in your pantry, sometimes one gets missed. In the interest of preserving your health, get into the habit of checking the seals before you open them. Signs that the seal is broken and that the food inside shouldn’t be consumed include:

When you press on the middle of the lid, the lid springs back after the pressure is released, indicating a bad seal.

When you tap the lid with a spoon, the resulting sound is dull, indicating a poor sealed lid

When you look at the lid, it should be concave, if it bulges, or even if it’s flat, it means the jar failed to seal properly.

If you open a glass jar and the lid doesn’t make a popping sound, the seal is bad and the food should be disposed of.

If there is any indication that the seal is leaking, throw the food away. Don’t even think about eating it.

Check the Condition of the Can

When you take a can or jar of food out of your pantry, take a second to inspect it. The jar should be in really good shape. Dents at either end of the can, bulges, cracks, rusts, or leaks indicate a problem and the food inside should be disposed of.

Sometimes the outside of the can or jar looks fine but when you open it up, things don’t look right. If the food appears cloudy but smells okay, boil the food for 10 minutes and taste it to see if it seems okay. If at any point the food smells bad, dispose of it. Starchy foods that have been canned will sometimes appear cloudy when opened while the contents are fine once cooked. In these cases it’s the starch that creates the cloudiness.

Do the contents have some bits of mold on them? There’s a generation of people who will scrape the mold away and eat the rest of the food, but this isn’t advised. The fact that the mold is there indicates that something happened to the can or jar and that botulinum could be present. The only exception to this is jams, which are naturally resistant to botulinum bacteria.

Sometimes you open a can or jar and the contents just smell … off. Although there are many things that could be causing this, it’s best to just dispose of the food and get another can. The odd odor could be created by invisible mold spores which you don’t want to consume.

If the food doesn’t taste right, don’t eat it. Yes, it’s possible that it’s simply a funny tasting batch or that the canning recipe was a little off. On the other hand, a strange taste can also indicate the presence of botulinum bacteria.

What if the Can or Jar Froze?

Cans and jars of food are often stored in places where the temperature of the room drops below the freezing point. In theory, freezing doesn’t hurt the contents, but it does cause them to expand, which in turn can ruin the seal. It’s generally considered to be in your best interest and refrain from eating from the frozen cans.

What about Pickles?

Technically, canned pickles could have botulimia, but it’s extremely rare. Because they’re preserved in acid brine, they are usually safe. The acidic brine normally prevents the growth of bacteria.

When it comes to eating canned foods, it’s always best to error on the side of caution. If you’re just not sure it’s safe, it’s best to toss it out. Getting sick isn’t worth it if you have the option to find food elsewhere.